The release engine's bell notification for a just-originated proposal
inserted through a fresh session while the proposal task sat uncommitted
in the engine's own transaction — the related_task_id FK rejected the
row and the ping was silently lost (caught live in the postgres log; the
DB-free Telegram DM still went out). send_ack_notification now accepts
db_session, forwarded to _create_notification so the insert joins the
caller's transaction, and the release engine passes its session. The
other five callers pass no task_id or reference committed tasks.
Co-authored-by: Renn F <rennf93@users.noreply.github.com>
